【单选题】Our teacher often tells us _______ our own cloth bags when shopping.
【单选题】Our teacher often speaks____and clearly in the class. [ ]
【判断题】风扇在工作时,风吹向散热器,以利散热器散热。
【简答题】______是人们对于新事物或有趣现象的直接兴趣,是在感知中由于兴奋性增强形成的一种不太稳定的愉悦倾向,属于始发状态的低层次兴趣,是由事物的新异刺激而引起的好奇心。
【单选题】Our teacher often stands us.
【判断题】冷却风扇在工作时,风是向散热器方向吹的,以利散热。()
【判断题】风扇在工作时,风是向散热器吹的,以利散热器散热。()
【单选题】Our teacher often tells us good students.
【单选题】有一节流阀,当阀口前后压力差 ∆ p=0.3MPa,阀的开口面积 A=0.1×10 -4 m 2 ,通过阀的流量 q=10L/min ,求 ( 1)若阀的开口面积 A 不变,但阀前后压力差为 ∆p 1 =0.5MPa ,通过阀的流量 q 1 = _____ L/min ; ( 2)若阀的前后压力差不变,但阀开口面积为 A 2 =0. 05 ×10 -4 m 2 ,通过阀的流量 q 2 = ____...
A.
q 1 = 12.91 L/min ; q 2 = 5 L/min ;
B.
q 1 = 13.9 2 L/min ; q 2 = 6 L/min ;
C.
q 1 = 14.9 3 L/min ; q 2 = 7 L/min ;
D.
q 1 = 15.9 4 L/min ; q 2 = 8 L/min
【单选题】Our teacher often tells us ____ the windows before we leave.